Twist-on wire connectors are well known in the art and generally comprise a hard shell with a spiral wire core located in a cavity in the shell. The ends of wires, which are to be connected together, are inserted into contact with the spiral wire core and the wires and twist-on wire connector are rotated with respect to each other to bring the electrical wires into electrical contact with each other. Typically, such wire connectors are assembled on automated machines that form the coil and the hard shell and automatically insert the the coil into the hard shell.
A modified twist-on wire connector, for example a waterproof twist-on wire connector, is a conventional twist-on wire connector that contains a sealant. The sealant containing twist-on wire connector generally comprise a hard shell, a coil, a wire penetrateable end cap and a sealant which has been injected into the cavity of the coil.
The manufacturer of twist-on wire connectors containing a sealant involves a number of steps including the formation of components for the twist-on wire connector, assembly of the components and the injection of sealant into a cavity in the spiral coil of the twist-on wire connector. As the components are generally small in size, i.e. about two inches or less in length the components can and have been readily assembled by automated apparatus. The components which can be assembled by automated apparatus can also be injected with sealant through an automated apparatus, however, one of the difficulties in assembling twist-on wire connectors with a sealant is to eliminate any faulty assembled twist-on wire connectors as well as those twist-on wire connectors that have do not have the proper amount of sealant.
An automated method and apparatus for making sealant containing twist-on wire connectors from basic components is shown in U.S. Pat. No. 5,771,578. This apparatus though use of numerous sensors addresses one of the difficulties in making twist-on wire connectors, which is to ensure that the sealant containing twist-on wire connectors are properly assembled. Typically, the components such as the shell and coil need to be assembled before a sealant can be injected into the coil. Occasionally, the coil or the sealant may not be properly assembled or the coil or the shell may not have been properly formed. In either case the result can be a faulty product. In order to minimize faulty products the U.S. Pat. No. 5,771,578 discloses an automated system that uses a number of optical sensors to detect the presence of components for assembly. A first sensor detects if the shells are being properly fed into the peripheral slots of a rotating table. A second sensor detects if the coils are being properly fed to a rotating assembly table. A third sensor determines if the coil is properly positioned in the shell and a fourth optical sensors determines if the caps are in position. Further optical sensors are used to determine if the coil is properly positioned in the shell. If the optical sensors detect that one or more of the twist-on wire connector components is not present on the assembly table or if the twist-on wire connector does not contain the proper amount of sealant the twist-on wire connector is rejected and is sent to a recycle bin.
The benefits of automation over manual assembly in reducing manufacturing cost in numerous industries are well known, however, while such automated systems using optical sensors can be used to form sealant containing wire connectors it requires an investment in specialized machinery not only for assembly of the components but also for injecting sealant into the twist-on wire connectors. To build systems to automatically perform both formation and assembly steps can be costly as well as costly to maintain the equipment for making assembled twist-on wire connectors. Typically, errors in settings or calibration of the optical sensors may result in unnecessary discarding of useable twist-on wire connectors or may allow connectors to pass that should have been sent to the recycle bin. A further disadvantage is that such machines may be useable for only one shape or size of components which may be used in the manufacture a waterproof twist-on connectors. Typically, a number of different sizes of wire connectors may be required by a customer. In contrast to use of increased automation the present invention provides an improvement to the process of forming twist-on wire connectors with a sealant therein through selectively reducing automation in the manufacture of a twist-on wire connector containing a sealant.